Read the first two chapters and so far I have really enjoyed the pacing with a light introduction to Phoenix and going a bit deeper with CRC, Plug and the generated code.
It was also nice to get some more insight in how the LiveView lifecycle fits together with the normal control flow and live_session.
Really looking forward to the rest of the book.
I enjoyed reading the first chapters of the book. All was going well until I got the message function Bcrypt.no_user_verify/0 is undefined (module Bcrypt is not available which I am trying to reconcile. I am uncertain how to formally post a question.
Maybe You did not load the dependencies after running mix phx.gen.auth…
That would be
mix deps.get
You can check if You have bcrypt_elixir in deps part of the mix.exs file
I checked the deps and actually ran mix deps.get and got the response
waynedavis@Waynes-MacBook-Pro pento % mix deps.get
Resolving Hex dependencies...
Resolution completed in 0.264s
Unchanged:
bcrypt_elixir 3.0.1
castore 1.0.1
comeonin 5.3.3
cowboy 2.9.0
cowboy_telemetry 0.4.0
cowlib 2.11.0
db_connection 2.5.0
......
The code that is giving me problem is
def valid_password?(_, _) do
Bcrypt.no_user_verify()
false
end
in Pento.Accounts.User. I looked up Bcrypt in Hexdocs and saw that bcrypt_elixir 3.0.1 and Bcryp were addressed on the same page. However, I could not see how Bcrpt call would be referred to the Elixir program bcrypt_elixir 3.0.1. I checked to see if I might have missed inserting an “alias” somewhere. Every thing was going well upto this glitch.
As for me, my name is Wayne Davis. I am a 75 year-old emeritus professor in engineering. I returned to programming about a decade. I had lerned Fortran and Pascal, but had not programmed for decades. I initially learned Erlang and then migrated to Elixir. I tried to master Phoenix several times but always ran into unresolved issues. Recently I decided to give PhoenixLive a try. But again I hit a glitch. I appreciate any assistance.
After experimentation I got the following message after I entered the mix phi.server command
waynedavis@Waynes-MacBook-Pro pento % mix phx.server
[error] Failed to start Ranch listener PentoWeb.Endpoint.HTTP in :ranch_tcp:listen([cacerts: :..., key: :..., cert: :..., ip: {127, 0, 0, 1}, port: 4000]) for reason :eaddrinuse (address already in use)
[error] Running PentoWeb.Endpoint with cowboy 2.9.0 at http failed, port already in use
[notice] Application pento exited: Pento.Application.start(:normal, []) returned an error: shutdown: failed to start child: PentoWeb.Endpoint
** (EXIT) shutdown: failed to start child: {:ranch_listener_sup, PentoWeb.Endpoint.HTTP}
** (EXIT) shutdown: failed to start child: :ranch_acceptors_sup
** (EXIT) {:listen_error, PentoWeb.Endpoint.HTTP, :eaddrinuse}
[notice] Application plug_cowboy exited: :stopped
Hi Davis!
As the error states, the application crashes since the port is already in use.
Normally, when I get this error, it’s because I already had the application or another phoenix app running on port 4000 in another shell or in the background.
Simply shut down the process that is hogging port 4000 and try again to start the application 
You have all my respect.
For the issue, as mentioned in the previous post, there is already something running on port 4000.
When there is a compilation problem, You can try the following steps, from the root folder of the project.
rm -rf _build
mix compile
If You are unsure about deps, You can try
rm -rf deps
mix deps.get
There are also mix commands to help You clean the project. You can have the full list, or on a specific command
mix help
mix help <command>
bcrypt and bcrypt_elixir are not the same package. But it is unfortunate they share the same name. If You look at the doc…
You will see the package name is bcrypt_elixir, but the main module name is Bcrypt. It can be confusing
I want to thank everyone for their replies. My bad. I was typing in localhost and the browser did an autofill which was taking me to the signup rather than the initial page at localhost:4000/guess. Anyway when I typed in the proper address it worked. Again thank you. By the way, I adopted Erlang/Elixir to support my former research in discrete-event simulation. The ability to perform concurrent computation upon thousands of independent trials is ideal. Additionally, I developed a new paradigm for the state evolution of discrete-event/task-execution systems which employs a regular grammar. The state can be represented by 2- or 4-tuples where each element itself can be either a numerical value or another tuple. The regular grammar is ideal for recursive functional programming.
Again thanks for your assistance.
Wayne
This chapter was a little lighter than the previous, but still had some very good content.
use statement required. 
I mentioned it in my previous post, but the syntax used to build the form is slightly outdated.
We no longer need to do :let={f} when declaring the form, and instead of <.input field={{f, :first_name}} ... /> we can do <.input field={@form[:first_name]} .... This is nice since the :let={f} stuff was pretty confusing imo.
Also, the assignment to the socket is slightly different, using the to_form function: assign(socket, :form, to_form(changeset)).
Once again, I’m sure this will be fixed for the final release.
I’m excited to start the next chapter about Function Components